U.S. patent number 5,922,626 [Application Number 08/874,039] was granted by the patent office on 1999-07-13 for self-adhering reinforcing material for nonwoven textile fabrics.
This patent grant is currently assigned to HP-Chemie Research and Development Ltd.. Invention is credited to Helmut Pelzer.
United States Patent |
5,922,626 |
Pelzer |
July 13, 1999 |
Self-adhering reinforcing material for nonwoven textile fabrics
Abstract
The self-adhering tape-like or fibrous reinforcing material to
be used according to the invention consists of laminates of at
least two or more co-extruded layers of at least one
high-temperature stable plastic material (A) and at least one
low-melting plastic material (B). The low-melting plastic material
(B) has self-adhering binder properties whereas the
high-temperature stable plastic material (A) is suitable for
conferring increased strength properties to nonwoven textile
fabrics, in particular in the automobile area.
Inventors: |
Pelzer; Helmut (Herdecke,
DE) |
Assignee: |
HP-Chemie Research and Development
Ltd. (Waterford, IE)
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Family
ID: |
25942842 |
Appl.
No.: |
08/874,039 |
Filed: |
June 12, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/EP95/04930 |
Dec 13, 1995 |
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Foreign Application Priority Data
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Dec 14, 1994 [DE] |
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44 44 505 |
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Current U.S.
Class: |
442/394; 428/515;
428/516; 442/398 |
Current CPC
Class: |
B32B
7/02 (20130101); Y10T 428/31913 (20150401); Y10T
442/678 (20150401); Y10T 442/674 (20150401); Y10T
428/31909 (20150401) |
Current International
Class: |
B32B
7/02 (20060101); B32B 027/28 () |
Field of
Search: |
;442/394,398
;428/515,516 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0310200 |
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Sep 1988 |
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EP |
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0340982 |
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Apr 1989 |
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EP |
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0469309 |
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Feb 1992 |
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EP |
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0584445 |
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Mar 1993 |
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EP |
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2180543 |
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Apr 1987 |
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GB |
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9323596 |
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Nov 1993 |
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WO |
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Primary Examiner: Bell; James J.
Attorney, Agent or Firm: Baker & Botts, L.L.P.
Parent Case Text
This application is a continuation-in-part of PCT/EP95/04930, filed
Dec. 13, 1995, designating the U.S., which is incorporated herein
by reference in its entirety.
Claims
I claim:
1. A self-adhering reinforcing material adapted for use as binders
for non-woven textile fabrics, comprising:
a high-temperature stable plastic material; and
a low-melting plastic material;
wherein said high-temperature stable plastic material and said
low-melting plastic material are layers of a laminate.
2. The self-adhering reinforcing material according to claim 1,
wherein said high-temperature plastic material and said low-melting
plastic material are co-extruded to form a laminate.
3. The reinforcing material according to claim 1, wherein said
high-temperature stable plastic material is selected from the group
consisting of poly(ethylene terephthalates), poly(butylene
terephthalates), polyamides, highly cross-linked polyolefins, and
mixtures thereof.
4. The reinforcing material according to claim 1, wherein said
low-melting plastic material is thermoplastic.
5. The material according to claim 3, wherein said low-melting
plastic material is selected from the group consisting of
high-pressure polyethylene, low-pressure polyethylene,
polypropylene, polystyrene, poly(methyl methacrylates),
ethylene-vinyl acetates, styrene-acrylonitrile, copolymers thereof,
copolymeric polyamides and copolymeric polyesters.
6. The material according to claim 1, wherein the melting range of
said high-temperature stable plastic material is at least
50.degree. C. higher than the melting range of said low-melting
plastic material.
7. The material according to claim 6 wherein the the melting range
of said high-temperature stable plastic material is 100.degree. C.
higher than the melt transition range of said low-melting plastic
material.
8. The reinforcing material according to claim 1, wherein said
material has a length of 2 to 50 mm.
9. The reinforcing material according to claim 1, wherein said
material is in the form of fibers having a cross-sectional
dimension of 50 to 100 microns.
10. The reinforcing material according to claim 1, wherein said
laminate comprises a first layer, a second layer and a third layer,
and wherein said first layer and said third layer comprise said
high-temperature stable plastic material and said second layer is
said low-melting plastic material.
11. The reinforcing material according to claim 1, wherein said
laminate comprises a first layer, a second layer and a third layer,
and wherein said first layer and said third layer comprise said
low-melting plastic material and said second layer comprises said
high-temperature stable plastic material.
12. A non-woven textile fabric, comprising said reinforcing
material according to claim 1.
13. A non-woven textile fabric according to claim 12, wherein said
fabric is a glass-fibre reinforced material, a glass-gauze
reinforced fibrous material, or a non-woven cotton fabric.
14. A non-woven textile fabric according to claim 12, further
comprising natural fibres with binders, natural fibres without
binders, synthetic fibres with binders, sythetic fibres without
binders, or mixtures thereof.
15. A non-woven textile fabric according to claim 14, wherein said
natural fibres are selected from the group consisting of cotton,
flax, jute, linen; and said synthetic fibres are selected from the
group consisting of poly(butylene terephthalates), poly(ethylene
terephthalates), nylon 6, nylon 66, nylon 12, viscose, and
rayon.
16. A non-woven textile fabric according to claim 12, wherein said
reinforcing material is present in said fabric at 5% to 50% by
weight based on said fabric.
17. A non-woven textile fabric according to claim 13, wherein said
reinforcing material is present in said fabric at 20% to 40% by
weight based on said fabric.
Description
The invention relates to a self-adhering tape-like or fibrous
reinforcing material having a binder property for nonwoven textile
fabrics, a process for the production thereof, the use of the
reinforcing material for the manufacturing of nonwoven textile
fabrics, the nonwoven textile fabrics manufactured this way, as
well as the use of these nonwoven textile fabrics in the automobile
sector.
In the automobile sector nonwoven textile fabrics are a frequently
used material of construction having a broad range of properties.
For example, phenolic resin bonded nonwoven textile fabric has been
used for a long time, among other things, because of the good
damping characteristics thereof as a material for supporting and
covered parts (pure or as composite) in automobile industry for
passenger car and truck manufacturing. In form of low-cost flat
fabric this product served initially and exclusively for
upholstering purposes. However, this material has presented itself
in a number of variants recently and may be used versatilely.
Moulded articles are especially preferred.
Phenolic resin bonded nonwoven textile fabric is available on the
market in bulk densities of from 50 to 1000 kg/cm.sup.3 with
thicknesses of from 5 to 30 mm. Is has to be described as so-called
porous composite comprising three phases (cotton, cured phenolic
resin, and air)--a material of construction, the profile of
properties of which can be modified within wide limits. Cotton is
fibrous, phenolic resin is present punctatedly and net-flat as a
kind of matrix.
By selecting the nonwoven fabric the acoustics and the strength of
the composite can be controlled particularly. Especially preferred
materials for the manufacturing of the nonwoven fabric are
glass-fibre reinforced or glass-gauze reinforced fibrous materials,
especially nonwoven textile fabrics containing binders, preferably
such consisting of a blended cotton fabric. These nonwoven fabrics
are brought to the desired strength by pressing at elevated
temperature.
The special features and the performance of this last-mentioned
product group explain itself by the chemical and morphological
structure of cotton as well as by the duroplast character of the
cured phenolic resins usually being employed as binder of the
nonwoven blended cotton fabric. Deformability, pressability of the
cotton, statistical occurance of bonding points, and the laminating
and/or surface action of the binder molecules adhering lengthwise
to the fibres and also condensated out in this manner are
additional quantities of influence.
The cotton withstands the manufacturing process practically without
modification of its physical-chemical properties. It imparts to the
product special features of quality such as sound-absorptive
capacity, good mechanical strength values, impact strength, and
shatter-resistance in the cold.
Especially preferred binders for the nonwoven fabrics are selected
from phenol-formaldehyde resins, epoxy resins, polyester resins,
polyamide resins, polypropylene, polyethylene and/or
ethylvinylacetate copolymers. After curing, phenolic resins have
the typical duroplastic properties being transferred to the final
product. Usually, the nonwoven textile fabric is manufactured from
the reclaimed cotton and powdery phenolic resin via the dry path.
Curing takes place either within the heating channel or via the
uncured half-finished good as intermediate within the press. For
the parts which are to be used within the passengers compartment a
select textile is employed.
In WO 93/23596 A1 are described nonwoven mouldable composites,
whereby 40-80 % by weight of a first thermoplastic fibre and a
second thermoplastic fibre having a lower melting point are
consolidated into a nonwoven structure and intermixed thoroughly
with the fibres. Subsequently, the nonwoven structure is heated to
a temperature above the melting point of the second fibre but below
that of the first fibre to liquefy the second fibre to form a
thermoplastic resin. Subsequently, the nonwoven textile fibre
structure is compressed to flow the binder resin into voids,
thereby displacing air and encapsulating the first fibre. Following
cooling, the structure has reduced air voids and does not shrink on
thermoforming. For this it is necessary to feed two different types
of fibres into the nonwoven textile fabric resulting in practice
frequently in achieving an inhomogeneous distribution of
fibres.
To feed reinforcing agents and binders it has been proposed in the
art to use also powdery thermoplastic binders in addition to the
reinforcing material, especially fibres. However, this feeding of
powdery binder has extremely important drawbacks for the
manufacturing of nonwoven textile fabrics, as in this case
compression is frequently performed using air pressure resulting in
blowing out at least a portion of the binder resin off the
mould.
To bind the binder resin to the reinforcing fibres so-called
composite fibres have been proposed in the art, in which the core
of the fibre and the outer coat have different melting points.
Thus, for example it is possible to manufacture composite fibres
having a high-temperature stable core being surrounded by a
low-melting, especially thermoplastic binder resin. When adding
these fibres to the nonwoven textile fabric, the nonwoven textile
fabric is compressed at a temperature being above the melting point
of the low-melting fibre material but below the melting point of
the reinforcement fibre core, a extremely strong compound with the
nonwoven textile fabrics can be achieved. However, manufacturing of
such composite fibres is extremely complex.
Consequently, the object of the present invention is to provide an
inexpensive self-adhering tape-like or fibrous reinforcing material
having a binder property for nonwoven textile fabrics. An
appropriate reinforcing material should be suitable for the use
within nonwoven textile fabrics, especially in nonwoven textile
fabrics being employed in the automobile sector in manifold
forms.
Therefore, a first embodiment of the present invention consists in
a self-adhering tape-like or fibrous reinforcing material having
binder properties for nonwoven textile fabrics consisting of
laminates of at least two or more co-extruded layers of at least
one high-temperature stable plastic material (A) and at least one
low-melting plastic material (B).
Therefore, the self-adhering reinforcing material according to the
invention is characterized by a composite structure having at least
two layers of at least two chemically and physically different
plastic materials (A) and (B). The essential difference between
plastic material (A) and plastic material (B) consists in the
temperature properties. Whereas plastic material (A) is selected
from high-temperature stable materials, therefore imparting a
reinforcing effect on the nonwoven textile fabric, the low-melting
plastic material (B), due to its binder properties, is suitable to
generate a good compounding between the textile fibres, the
reinforcing fibres and itself from the high-temperature stable
plastic material (A).
In a preferred embodiment of the present invention, the
high-temperature stable plastic material (A) is selected from
polyethylene terephthalate, polybutylene terephthalat, polyamides,
and highly cross-linked polyolefins such as polyethylene and/or
polypropylene. The melting range preferably should be within the
temperature range above 100.degree. C., especially above
150.degree. C. Temperatures in the range above 300.degree. C. are
especially preferred.
The low-melting plastic materials (B) preferably have thermoplastic
properties. As is generally known, thermoplastics can be processed
to moulded articles in the softened state by pressing, extruding,
injection moulding, or other moulding processes. In accordance with
the present invention the choice of thermoplastic plastic materials
is especially defined by the subsequent purpose of application. In
this connection, it has essentially to be adjusted to the
subsequent temperature load of the nonwoven textile fabric.
Especially preferred thermoplastic plastic materials (B) are
selected from low-melting high-pressure process polyethylene,
low-pressure polyethylene, polypropylene, polystyrene, polyethylene
methacrylates, ethylene-vinyl acetate, styrene-acrylonitrile, the
copolymers thereof and copolymeric polyamides and polyesters.
Especially preferred in this are the bulk plastics due to the low
costs. The melting range should preferably range from 70 to
100.degree. C., especially from 70 to 80.degree. C.
Contrary to the composite fibres according to the art, in which the
microscopic and macroscopic properties of the core and the outer
shell differ, in the reinforcing materials according to the present
invention different temperature properties are present in the
layers.
The inventive reinforcing materials are to be used in nonwoven
textile fabrics known as such. Therefore it is necessary to match
the melting behavior as well as the forming behavior of the plastic
materials (A) and (B) with these materials.
The temperature properties of the different materials of the
inventive reinforcing materials can be defined especially well by
the melting ranges of the plastic materials. Within the meaning of
the present invention it is especially preferred the melting range
of the high-temperature solid plastic material (A) is at least
50.degree. C., especially 100.degree. C. above the melting range of
the low-melting plastic materials (B).
To achieve a distinct reinforcing character it is especially
preferred within the meaning of the present invention to adjust the
diameter and the length of the self-adhering reinforcing materials
especially. Especially preferred widths and heights within the
meaning of the present invention are from 20 to 500 .mu.m,
especially from 50 to 100 .mu.m. Within said range especially good
reinforcing properties are achieved. The same way, it is preferred
to adjust the length of the self-adhering reinforcing materials to
a range of from 2 to 50 mm, especially of from 5 to 20 mm.
The basic concept of the present invention is based on a structure
having at least two layers of two co-extruded plastic materials (A)
and (B) being bonded to each other without additional adhesives.
However, in the same manner it is preferred according to the
present invention to increase the number of layers. Therefore,
without any difficulty layer structures of three, four, five, or
six layers of the respective materials (A) and (B) are possible.
Especially preferred within the meaning of the present invention
is, however, an altogether three-layer layer structure, in which
the plastic materials (A) and (B) alternate as follows:
One layer of the high-temperature solid plastic material (A) is
covered by respective layers of the low-melting plastic material
(B) on the top side and the bottom side of the high-temperature
solid plastic material (A). In the same way, however, an inverse
layer structure is possible, in which one layer of the low-melting
plastic material (B) is covered by two layers of the
high-temperature solid plastic material (A). In this case, the
reinforcing material upon using has to be brought to a temperature
allowing a leaking of the low-melting plastic material (B) out of
the sandwich arrangement.
A further embodiment of the present invention consists in the
process for the production of the reinforcing materials defined at
the beginning. These can be obtained especially by co-extruding at
least two layers of a high-temperature solid plastic material (A)
and one low-melting plastic material (B) at a temperature within or
above the glass transition ranges of the plastic materials (A) and
(B) and the subsequent cutting or disintegrating to the desired
dimensions by cutting, pressing, or striking tools.
The co-extrusion of the different plastic materials (A) and (B) is
of special importance in the inventive process. Whereas the
extrusion of low-melting plastic materials (B) usually proceeds
without problems, extrusion of high-temperature solid plastic
materials (A) in practice is often connected with problems, as the
materials often crosslink or even decompose at high temperatures.
Therefore, it is necessary to adjust the extrusion conditions to
the required conditions, especially to the high-temperature solid
plastic materials (A).
After the manufacturing of a flatlike laminate from the plastic
materials (A) and (B) by co-extrusion, subsequently during an
additional operating step a self-adhering tape-like or fibrous
reinforcing material is produced. The dimensions defined above can
be obtained by cutting, pressing, or striking.
Therefore, an additional embodiment of the present invention
consists in the use of the self-adhering tape-like or fibrous
reinforcing material as defined at the beginning for the
manufacturing of nonwoven textile fabrics, especially glass fibre
reinforced or glass gauze reinforced fibre materials and nonwoven
cotton fabrics. Here, a partial or complete replacement of the
normally employed phenolic resin binders can be achieved.
The nonwoven textile fabrics according to the invention due to the
special features such as high stiffness of compressed nonwoven
fabrics are superior to plastic sheets of known plastic materials
as well as glass fibre reinforced polypropylene or similar
materials having a similar weight. Moreover, the acoustic
properties arising from the porosity and the layer structure of the
material impart the materials a special suitability for the
automobile section.
Nonwoven textile fabrics within the meaning of the present
invention comprise preferably natural fibres, especially cotton,
flax, jute, linen, but as well synthetic fibres such as
polybutylene terephthalates, polyethylene terephthalates, nylon 6,
nylon 66, nylon 12, viscose, or rayon as textile fibre, optionally
in addition with usual binder.
The type and the amount of self-adhering tape-like or fibrous
reinforcing materials to be used is essentially determined by the
purpose of application of the nonwoven textile fabrics. Thus, in
general the use of from 5 to 50% by weight, especially of from 20
to 40% by weight of the self-adhering tape-like or fibrous
reinforcing material is employed, based on the nonwoven textile
fabric. In case additional usual binders are to be used within the
nonwoven textile fabrics it is possible, however, to reduce the
amount of the self-adhering tape-like or fibrous reinforcing
material accordingly.
Another embodiment of the present invention relates to a process
for the preparation of the above defined nonwoven textile fibre
fabrics. The textile fibre materials are appropriately combined
with the self-adhering tape-like and fibrous reinforcing materials
and are obtained by pressing at a temperature above the melting
range of the low-melting plastic material (B) but below the
decomposition range of the high-temperature stable plastic material
(A). According to the present invention, a temperature range of
from 120 to 250.degree. C., in particular from 180 to 250.degree.
C., is particularly preferred since nonwoven textile fibres used so
far in the prior art are also pressed at such a temperature. In
this temperature range, certain materials will cross-link such that
a particularly strong compound will form.
The composite materials according to the invention can be used as
such in the automobile section. According to the present invention,
it is also preferred, however, to provide them with decorative
layers, for instance, carpet floor coverings.
Another embodiment of the present invention consists in the special
use of the above defined composite materials in the automobile
area. It is particularly preferred to use the composite materials
according to the invention for acoustic absorption in the areas of
the engine hood, scuttle (on both sides), tunnel, door, roof,
legroom, and ventilation duct, as well as an optionally
self-supporting base for interior linings, in particular for
instruments coverings, tunnel linings, door linings, seatback
linings, and spare wheel coverings, as well as for parts with
double functions, especially as roof lining, hat rack, filing
piece, luggage trunk matting, and wheel box lining.
The self-adhering reinforcing material of this invention comprises
a bi-layer or multi-layer made up of at least one thermoplastic
material and at least one thermosetting material laminated
together. These materials are typically formed as a bi- or
multi-layer sheet and subsequently cut into ribbons or reduced to
fibers by physical force, e.g., by cleavage or comminution.
In one embodiment of this invention, a self-adhering reinforcing
material which is adapted for use as a binder for non-woven textile
fabrics is provided. The reinforcing material is a laminate which
has at least one layer of a high-temperature stable plastic
material and at least one layer of a low-melting plastic material.
As used herein, high-temperature stable plastic materials are
materials composed of polymers that remain solid at temperatures
used in forming and/or processing non-woven fabrics according to
this invention, preferably the polymers do not melt at 100 C. or
higher. As used herein, low-melting plastic materials are materials
composed of polymers that melt or exhibit thermoplasticity at
temperatures in the upper ranges of the temperatures used in
forming and/or processing non-woven fabrics according to this
invention, for example, from 70 C. to 100 C. In an alternative
embodiment of the invention, the high-temperature stable plastic
material and the low-melting plastic material are co-extruded to
form a laminate. In a further embodiment of this invention, the
laminate sheets can be formed into ribbons or fibers by cutting or
striking. Alternatively, material of the desired size and shape may
be obtained by running the laminate through presses.
In another embodiment of this invention, a method for preparing
self-adhering reinforcing materials adapted for use as binders of
non-woven textile fabrics is provided using at least one layer of
high-temperature stable plastic material and at least one layer of
low-melting plastic material and forming a laminate from the layers
of high-temperature stable plastic material and low-melting plastic
material. In an alternative embodiment of the invention, the layers
of high-temperature stable plastic material are provided by
extruding high-temperature plastic materials and the layers of
low-melting plastic material are provided by extruding low-melting
plastic materials. In another alternative embodiment, the laminate
is formed by co-extruding the layers of high-melting stable plastic
material and low-melting plastic material.
In another embodiment of this invention, a non-woven textile fabric
is provided which includes the self-adhering reinforcing material
adapted for use as a binder for non-woven textile fabrics which is
a laminate of at least one layer of high-temperature stable plastic
material and at least one layer of low-melting plastic
material.
In yet another embodiment of this invention, a method for the
preparation of non-woven textile fabrics is provided by pressing a
textile fiber material and a self-adhering reinforcing material,
which is a laminate of layers of high-temperature stable plastic
material and low-melting plastic material, at a temperature above
the melting range of the low-melting plastic material but below the
melting range of the high-temperature stable plastic material.
Preferably, the high-temperature stable plastic material is a
duroplastic that will melt at high temperature when first extruded,
but after curing will decompose at elevated temperature before
melting. In this further embodiment, the temperature of the
pressing step is lower than the decomposition temperature of the
heat-temperature stable plastic material.
All publications and patent applications mentioned in this
specification are indicative of the level of skill of those skilled
in the art to which this invention pertains. All publications and
patent applications are herein incorporated by reference to the
same extent as if each individual publication or patent application
was specifically and individually indicated to be incorporated by
reference.
* * * * *